In the prior art various systems are known which aim at determining the event which is the hitting of a golf ball by a golf club.
The patent U.S. Pat. No. 6,030,109 describes such a device. Said patent relates to a device for the automatic incrementing of the number of hits produced by one or more golfers on a golf course. A sound sensor, which has to be situated a short distance from the ball, for example on the ankle of a user, coupled to a processing means, makes it possible to detect the particular sound emitted by a golf club hitting a golf ball. Such a device, in addition to the disadvantage of having to be situated a short distance from the golf ball, which is neither practical nor comfortable, is not very reliable with regard to determining the time of the actual hitting of the golf ball by the user's golf club and with regard to the fact that detected noise corresponds well to an actual hit by the golfer in question.
As a variant, the document US 2005/282,650 describes a computer worn on the wrist, the detection of the occurrence of a golf hit and the recording of an item of data relating to the game of golf. However, interference detections of false occurrences of golf balls, like the test shots carried out by the golfer without a ball, are likely falsify the recording of the data.
US 2004/073,325 describes a system for detecting the hitting of a golf ball by sound sensing. This document also describes a system of tracking of the golf club by detection of an inaudible air modulation signal.